Manufacture of electric conductors.



* lirtrrnn Sirnrns Parent Orrrcn,

SHERARD OSBORN COlVPER-OOLES, OF LONDON, ENGLAND, ASSIGNOR OFTHREE-FIFTHS TO JAMES NOEL SPARKS AND THOMAS FRAME THOMSON, OF SAMEPLACE, AND JOHN STEWARTMACARTHUR, OF POLLOKSI-IIELDS,

SCOTLAND.

MANUFACTURE OF ELECTRIC CONDUCTORS;

SPECIFICATION forming part of Letters Patent No. 628,770, dated July 11,1899.

Application filed December 24,1897. Serial No. 663,423. (No model.)

To all whom it may concern/.

Be it known that I, SHERARD OSBORN Cow- PER-COLES, a subject of theQueen of Great Britain, residing at London, in the county of 5Middlesex, England, have invented certain new and useful improvements inand connected with the manufacture of electric conductors for use asleading-in wires or strips in the manufacture of incandescent electric1o lamps, vacuu m-tubes, and the like, (for which I have receivedLetters Patent in England, No. S42,dated January 13, 1896,and in France,No. 260,512, dated October 17, 1896;) and I do hereby declare that thefollowing is a full, I5 clear, and exact description of the invention,

which will enable others skilled in the art to which it appertains tomake and use the same. The object of this invention is to producemetallic conductors suitable for use as lead- 20 ing-in wires orstripsin the manufacture ofincandescent electric lamps,Vacuum-tubes, andthe like in substitution for the platinum wireshithertousedforthepurpose. Attemptshave been made to emply iron wire forthis pur- 25 pose, and it has been proposed to coat such wires withanother metal, such as tin; but these attempts have hitherto failed.discovered that it is necessary to secure successful results to employpure iron, or iron 0 which is-practically pure, and that ordinarycommercial iron is not suitable for the purpose. I have also discoveredthat it is necessary to coat or cover the iron conductors with an alloynot readily oxidizable and ofa 5 low melting-point, such that it willbecome fused when the heat necessary for effecting the scaling in of theconductors is applied. After receiving such coating or covering andprior to the sealing-in process the conduc- 0 tors may receive a coatingof vitreous material. According to my invention I employ,

preferably, chemically-pure iron produced by electrolysis, which may bedone by employing scrap-iron as an anode,with a cathode 5 of steel orother metal, from which deposited iron may be readily removed, and anysuitable electrolyte, such as a solution of iron sulfate or sulfuricacid or the like.

The

I have electrolytically deposited iron is stripped from the cathode andformed into the neces- 5o sary shape to constitute the required wires orstrips by annealing and drawing. All traces of oxidation or impurityshould then be removed therefrom and the wires or strips thus preparedbe passed through a bath containing the molten alloy. Good results canbe obtained with an alloy composed of fifty parts (by Weight) of tin,twenty-five parts of lead, twenty-five parts of cadmium, and one part ofaluminium; but Ido not limit myself to this particular alloy. To insurea perfect coating, I find it advantageous to cover the surface of thebath of molten alloy with zinc chlorid or other suitable flux. 7

In applying the wires or strips to the lamps, tubes, or the like a thincoating of glass may be applied (by spinning or wrapping, for example,or immersion in abath of molten glass) to the parts of the wires orstrips which are to be sealed into the bulb, tube, or the like. Thesealing in of the Wires or strips is then effected by the application ofheat in the ordinary way, when, owing to the iron employed being in apure or practically pure state and the alloy covering it being of therequisite low melting-point, the wires orstrips become hermeticallyattached to the glass of the bulb, tube, or the like through which theypass.

It is found that pure iron will expand almost in the same ratio asglass, and consequently there is no breakage of the glass in cooling,Whereas ordinary iron has a coefficient of expansion considerablydifferent from'that of glass, and breakage of the glass occurs whereattempts are made to unite such iron and glass. The glass appears toflux or combine with the coating metal of low fusingpoint, and thus forma perfect seal with the pure iron wire.

Having fully described my invention, what 90 I claim, and desire tosecure by Letters Patent, is-

1. An electric conductor composed of practically pure iron and providedwith a metallic coating having a low melting-point.

2. An electric conductor composed of prac- 5. The method of producingelectric con- (luctors or leading-in wires, which consistsin firstsubjecting commercial iron to an electrodepositing operation, thenremoving all traces of oxidation or impurities therefrom, forming 1 saidiron in strips, and then passing said strips through a bath of moltenalloy, the surface of which is covered with a suitable flux.

Sll ERARI) OS BORN (OWPER-COLES.

\Vitnesses:

CHAS. A. ALLISON, HARRY A. MoLELLAN.

